pkg/47440: `make checksum' doesn't refetch even if FAILOVER_FETCH is set

[Taylor R Campbell <campbell+pkgsrc%mumble.net@localhost>]

>Number:         47440
>Category:       pkg
>Synopsis:       `bmake checksum' doesn't refetch even if FAILOVER_FETCH is set
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Jan 13 21:20:01 +0000 2013
>Originator:     Taylor R Campbell <campbell+pkgsrc%mumble.net@localhost>
>Release:        pkgsrc-current
>Organization:
>Environment:
>Description:

        If a downloaded distfile has a bad checksum, `bmake fetch' does
        nothing to refetch it since it appears to be up-to-date, and
        `bmake checksum' simply fails.  If you set FAILOVER_FETCH=yes,
        `bmake fetch' looks at the checksum only if the file was absent
        to begin with in order to decide whether to refetch it, which
        doesn't help if the file has already been downloaded but got
        corrupted on disk.

>How-To-Repeat:

        Corrupt some of your distfiles on disk and try to run a bulk
        build or whatever.

>Fix:

        Yes, please!